Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease

The usefulness of stress 201Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 90% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left main coronary artery disease.     

Noninvasive perfusion control by thallium-201 myocardial scintigraphy after coronary artery bypass surgery

Thallium-201 myocardial scintigraphy, which has been shown accurate in the assessment of myocardial perfusion, was employed in the evaluation of 34 patients after coronary artery bypass surgery. In 28 patients (82.4%), there was a clear correspondence in the postoperative studies between the defects shown on scintigraphy and the coronary artery stenosis documented by arteriography. Thallium imaging after coronary artery bypass revealed an increased or newly developed scintigraphic defect in eight of 10 patients with recurrent angina. Follow-up arteriography in these 10 patients revealed occlusion or stenosis of the bypass graft in five, perioperative myocardial infarction in two, and increased stenosis of a preoperatively less occluded artery in two. In 24 patients with postoperative clinical improvement or relief of angina,²⁰¹Tl scintigraphy revealed complete normalization of thallium uptake in three, improvement of uptake in 17, and unchanged uptake defects in four. Presented at the 5. Herbsttagung der Deutschen Gesellschaft für Kreislaufforschung, October 28, 1978, Berlin.     

Incremental diagnostic value of dipyridamole echocardiography and exercise thallium 201 scintigraphy in the assessment of presence and extent of coronary artery disease

Background  

The incremental diagnostic information of two noninvasive tests for the detection of coronary artery disease (CAD), dipyridamole echocardiography, and exercise²⁰¹Tl myocardial scintigraphy was assessed in a series of 102 patients with ordered logistic regression and receiver-operating characteristic curves.     

Sixty-four-slice computed tomography coronary angiography compared with myocardial perfusion scintigraphy for the diagnosis of functionally significant coronary stenoses in patients with a low to intermediate likelihood of coronary artery disease

Background. Multislice computed tomography coronary angiography (CTA) was proposed as a method for investigating possible coronary artery disease (CAD) in patients who present with chest pain but with a low to intermediate likelihood of CAD. Sixty-four-channel CTA was compared prospectively with ^99mTc-tetrofosmin myocardial perfusion scintigraphy (MPS) (as the gold standard in the detection of flow-limiting stenoses) for the detection of functionally significant CAD. Methods and Results. Fifty-two consecutive symptomatic patients with a low to intermediate likelihood of coronary artery disease, and who were referred for MPS, also underwent CTA. The CTA datasets were analyzed by two experienced observers who were blinded to the MPS data, and coronary artery segments were reported as <50%, 50% to 69%, 70% to 99% stenoses, or occluded. The MPS images were similarly analyzed for inducible perfusion abnormalities, and coronary territories were identified. At the patient level, agreement between CTA and MPS for CTA lesions at ≥50% was 87% (sensitivity, 100%; specificity, 84%; positive predictive value, 50%; negative predictive value, 100%). For CTA lesions, agreement at ≥70% was 96% (sensitivity, 86%; specificity, 98%; positive predictive value, 86%; negative predictive value, 98%). Conclusions. In patients with a low to intermediate likelihood of CAD, there is good correlation between MPS and CTA for the detection of functionally significant coronary artery stenoses when CTA detects a narrowing of ≥70% severity. Computed tomography coronary angiography stenoses of 70% should be used to determine functional significance, and not 50%, as is the usual practice at present. This work was funded by an unrestricted research grant from the United Kingdom Defence Postgraduate Medical Deanery. We also thank the Royal Air Force Medical Branch for financial support.     

Impact of Non-obstructive left main disease on the progression of coronary artery disease: A PARADIGM substudy

BackgroundThe aim of the study is examine the impact of non-obstructive (<50%stenosis) left main (LM) disease on the natural history of coronary artery disease using serial coronary computed tomography angiography (CTA).MethodsCTAs from the PARADIGM (Progression of atherosclerotic plaque determined by computed tomographic angiography imaging) study, a prospective multinational registry of patients who underwent serial CTA at a ≥2 year interval were analyzed. Those without evidence of CAD on their baseline scan were excluded, as were those with obstructive left main disease. Coronary artery vessels and their branches underwent quantification of: plaque volume and composition; diameter stenosis; presence of high-risk plaque.ResultsOf 944 (62 ± 9 years, 60% male) who had evidence of CAD at baseline, 444 (47%) had LM disease. Those with LM disease had a higher baseline plaque volume (194.8 ± 221mm3 versus 72.9 ± 84.3mm3, p < 0.001) and a higher prevalence of high-risk plaque (17.5% versus 13%, p < 0.001) than those without LM disease. On multivariable general linear model, patients with LM disease had greater annual rates of progression of total (26.5 ± 31.4mm3/yr versus 14.9 ± 20.1mm3/yr, p < 0.001) and calcified plaque volume (17 ± 24mm3/yr versus 7 ± 11mm3/yr, p < 0.001), with no difference in fibrous, fibrofatty or necrotic core plaque components.ConclusionThe presence of non-obstructive LM disease is associated with greater rates of plaque progression and a higher prevalence of high-risk plaque throughout the entire coronary artery tree compared to CAD without LM involvement. Our data suggests that non-obstructive LM disease may be a marker for an aggressive phenotype of CAD that may benefit from more intensive treatment strategies.     

合并多支血管病变的无保护左主干的介入治疗

目的：分析合并多支血管病变的无保护左主干（ULMCA）患者接受冠脉介入治疗（PCI）的近期安全性及有效性。方法：整理、总结我院自2002—04～2007—08所行的29例合并多支血管病变的ULMCA患者的支架植入术,分析其病变特征、手术成功率及随访结果。结果：即刻手术成功率达100％。25例（86．2％）术后1个月随访,主要心脏事件发生率为0％。结论：对于心功能正常、低危的左主干病变患者,PCI治疗是安全有效的。     

Underestimation of extent of ischemia by gated SPECT myocardial perfusion imaging in patients with left main coronary artery disease

Background  There have been limited data regarding the value of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for the detection of left main coronary artery disease (CAD). Methods and Results  We studied 101 patients with angiographic left main CAD (≥50% stenosis) and no prior myocardial infarction or coronary revascularization who underwent gated exercise or adenosine stress technetium 99m sestamibi SPECT MPI. By perfusion assessment alone, high-risk disease with moderate to severe defects (>10% myocardium at stress) was identified in only 56% of patients visually and 59% quantitatively. Absence of significant perfusion defect (≥5% myocardium) was seen in 13% of patients visually and 15% quantitatively. However, by combining visual perfusion data and nonperfusion variables, especially transient ischemic dilation, 83% of patients were identified as high risk. Conclusions  The findings of this study demonstrate that assessment of perfusion data alone by visual or quantitative SPECT MPI analysis underestimates the magnitude of left main CAD. The combination of perfusion and nonperfusion abnormalities on gated MPI identifies high risk in most patients with left main CAD. This study was presented in part at the American College of Cardiology 56th Annual Scientific Session, March 24–27, 2007, New Orleans, La. This work was supported in part by grants from Bristol-Myers Squibb Medical Imaging, Billerica, Mass, and Astellas, Deerfield, Ill.     

Myocardial scintigraphy with thallium-201 and technetium-99m-hexakis-methoxyisobutylisonitrile in left bundle branch block: a study in patients with and without coronary artery disease

In left bundle branch block (LBBB) thallium-201 myocardial scintigraphy frequently reveals septal abnormalities in the absence of coronary artery disease (CAD) and gives rise to false-positive results in patients with suspected CAD. It has not yet been clarified which pathophysiological mechanism is responsible for these perfusion abnormalities. A total of 66 patients with constant LBBB were investigated with ²⁰¹T1 or technetium-99m-hexakis-methoxyisobutylisonitrile (MIBI), 62 underwent coronary angiography. Of 12 patients without left anterior descending artery (LAD) or right coronary artery (RCA) stenoses, 11 had a reversible septal activity deficit after ²⁰¹T1 stress injection, whereas 20 of 22 patients without relevant CAD showed a constant stress/rest septal deficit using MIBI. Regarding patients with significant LAD and/or RCA stenoses, both radiopharmaceuticals almost always showed a reversible septal deficit: with ²⁰¹T1 in 15 of 16 individuals and with MIBI in 14 of 15. In 12 patients ²⁰¹T1 was reinjected at rest. In those who had LAD or RCA stenoses (n = 5), early septal activity uptake after stress injection was poorer than that after rest injection; in the absence of CAD (n = 7), septal stress uptake corresponded with that of rest injection. It is concluded that septal perfusion abnormalities in LBBB and the absence of CAD are characterized by an exercise-independent reduction of septal blood flow per mass of viable myocardium and that stress/rest injection protocols of myocardial perfusion tracers are able to differentiate between LBBB with and without CAD.Dedicated to Prof. Dr. Dr. h.c. H. Hundeshagen on the occasion of his 65th birthday Correspondence to: W.H. Knapp     

Worsening of left ventricular ejection fraction induced by dipyridamole on Tl-201 gated myocardial perfusion imaging predicts significant coronary artery disease

BACKGROUND: Vasodilator stress on myocardial perfusion imaging has been found to induce ischemic stunning, which may present as transient worsening of left ventricular ejection fraction (LVEF) or regional wall motion abnormality. This study aimed to evaluate the significance of stress-induced worsening of LVEF in the diagnosis of coronary artery disease (CAD) on dipyridamole thallium 201 gated single photon emission computed tomography (SPECT). METHODS AND RESULTS: The study included 126 patients who underwent dipyridamole Tl-201 gated SPECT and coronary angiography within 3 months. Poststress and 4-hour rest images were obtained, and LVEF was calculated by use of automated software (QGS 3.0). A decrease in LVEF of 6% or greater from rest to poststress was considered significant, and this threshold was determined by the serial reproducibility assessment of Tl-201 gated SPECT. If worsening of LVEF was used as the criterion for detecting significant CAD (> or = 70% coronary stenoses in > or = 1 vessel), the sensitivity, specificity, positive predictive value, and negative predictive value were 35%, 93%, 90%, and 44%, respectively. CONCLUSION: Dipyridamole-induced worsening of LVEF, as shown by Tl-201 gated SPECT, is a valuable nonperfusion marker of significant CAD. Although the sensitivity of LVEF worsening in detecting significant CAD is only 35%, the specificity is as high as 93%.     

Clinical characteristics and referral pattern of patients with left ventricular dysfunction and significant coronary artery disease undergoing radionuclide imaging

BACKGROUND: Many observational studies that predict patient outcomes have examined the use of myocardial perfusion imaging results. However, a referral pattern for radionuclide testing could bias these analyses and should be determined. These patients may also differ with regard to the extent of coronary artery disease (CAD). All of these differences must be incorporated into proper outcomes examinations. We sought to identify the nuclear perfusion imaging referral pattern for patients with left ventricular (LV) dysfunction and significant CAD. METHODS AND RESULTS: Patients with LV dysfunction and CAD (n = 2951) meeting our inclusion criteria were compared by receipt or absence of radionuclide perfusion testing within 6 months before or after angiography. Pearson chi2 and Kruskal-Wallis analyses were used to examine differences in baseline characteristics and catheterization results, whereas logistic regression modeling was applied to predict nuclear imaging referral before and after catheterization. Precatheterization nuclear cohort patients were more likely to be minority patients (odds ratio [OR], 1.34; P =.0083) with previous cardiac revascularization (OR, 2.27; P =.0001), Charlson comorbidity index greater than 1 (OR, 1.146; P =.0091), and heart failure symptoms (OR, 1.62; P =.0001) than those without imaging. They were less likely to have a myocardial infarction (OR, 0.464; P =.0001). After catheterization, the nuclear patients were more likely to have had congestive heart failure (OR, 1.452; P =.0019), a myocardial infarction (OR, 1.353; P =.0371), an ejection fraction lower than 30% (OR, 1.058; P =.0002), and prior revascularization (OR, 1.880; P =.0001). In addition, they had fewer diseased vessels (OR, 0.731; P =.0001). CONCLUSIONS: Bias exists in nuclear referral for patients with LV dysfunction and significant CAD and must be considered when interpreting observational studies on this topic.     

Side effect profile and tolerability of adenosine myocardial perfusion scintigraphy in patients with mild asthma or chronic obstructive pulmonary disease

Background Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive pulmonary disease (COPD). Recent evidence suggests that this effect may be dependent on the severity of disease. This study investigates the tolerability of adenosine stress in patients with mild asthma or COPD undergoing myocardial perfusion scintigraphy. Methods and Results In this case-control study patients with known or suspected mild asthma or COPD were pretreated with an inhaled β₂-adrenergic agonist and adenosine titrated up to the maximal dose of 140 μg·kg⁻¹·min⁻¹ over a period of 6 minutes. The occurrence of side effects and test tolerability were compared between the airway disease group and 72 control subjects. Of 1261 patients, 124 had known or suspected airway disease; of these, 72 (58%) were suitable for adenosine stress. The proportion of tests completed as per protocol in the asthma/COPD group was similar to that of control subjects (93% vs 100%, P=.06). Dyspnea (n=38 [53%] in asthma/COPD group vs n=25 [35%] in control group, P=.03) and chest pain (n=14 [19%] in asthma/COPD group vs n=16 [22%] in control group, P=.7) were the most common side effects, and these were mostly mild and well tolerated. Bronchospasm occurred in 5 patients with asthma/COPD but reverted shortly after discontinuation of the adenosine infusion. Aminophylline was not required in any case. Conclusions A stepwise 6-minute adenosine infusion with prophylactic β₂-adrenergic agonist is safe and well tolerated in patients with mild asthma or COPD.     

慢性稳定型冠心病的核素心肌灌注显像临床应用进展

多项临床试验证明,核素心肌灌注显像在冠心病诊断、危险度分层、预后判断、病人处理方案等方面具有突出的作用和优越的价值。在ACC/AHA(美国心脏病学院/美国心脏学会)有关冠心病和核心脏病学指南中,心肌灌注显像的上述作用得到了充分肯定。合理应用该项技术可以提高对冠心病诊断、处理的整体水平,并使有限的医疗资源得到更合理利用,这在我国目前显得十分迫切和需要。     

Thallium-201 myocardial scintigraphy in coronary triple-vessel disease: An attempt to increase sensitivity using quantitative methods

In order to increase the sensitivity of thallium-201 exercise scintigraphy in patients with triple vessel coronary disease (TVD), we first examined retrospectively myocardial scintigrams of 179 patients with TVD, as documented subsequently by cardiac catheterization. Ischemia had been diagnosed visually in 141 (79%), scar without ischemia in 25 (14%) and no apparent perfusion defect in 13 (7%) cases. The subset of TVD patients without scintigraphic ischemia (i.e. those with scar or no perfusion defect) was then compared to a control group with normal coronary angiography using four quantitative criteria: (1) in preset-count analog images, a quotient of the exposure times rest image/stress image; (2) in preset-time digital images, a quotient of counts/pixel in stress image/rest image using two different myocardial regions of interest (ROI); (3) a similar quotient using paracardial lung ROIs of three different sizes; (4) the absolute values of stress lung uptake. Quotients (1) and (2) were expected to be lower in TVD patients than in normal controls due to exercise-induced global ischemia, quotient (3) and value (4) were expected to be higher due to exercise-induced left ventricular dysfunction with increased lung uptake of thallium-201. All results showed a tendency to confirm these hypotheses; significant differences (P<0.05) between patients and controls were obtained in all lung quotients and in 3 of 12 myocardial quotients. No significant differences were observed in the exposure time quotients of preset-count images and in the stress lung uptake. Due to overlapping values, it was not possible to fix normal and pathological ranges of any quotient. It is concluded that the increased ratio of stress/rest lung uptake reflecting exercise-induced pulmonary venous congestion seems to indicate TVD in apparently normal thallium-201 scintigrams in a large number of patients.     

Prognostic predictors and outcomes in patients with abnormal myocardial perfusion imaging and angiographically insignificant coronary artery disease

Background. Abnormal stress myocardial perfusion imaging studies (SMPI) with angiographically insignificant coronary artery disease (ICAD) have often been labeled “false positive” scans. We evaluated the prognostic predictors and outcomes in an unselected patient population having abnormal SMPI and ICAD (study group) over a 24 month period of follow-up. Methods. Retrospective study of consecutive patients who had SMPI and subsequent coronary angiography showing ICAD within 6 months of index scan with matched control group with normal scans. Major Adverse Cardiac Events (MACE) were defined as the first occurrence of death or myocardial infarction (MI). Patients were followed up to 24 months from the time of their SMPI to identify the development of MACE. Results. One hundred and twenty five patients formed the study group and one hundred and thirty six patients formed the control group. Over a two-year follow up, approximately 13% of the study group had MACE as compared to 4.2% in the control group (P=022). Abnormal SMPI, EF<40% and chronic kidney disease (GFR<60 ml/min) were independent predictors of MACE in the study group. In multivariate analysis for MACE prediction, chronic kidney disease remained the sole independent predictor regardless of size or severity of perfusion abnormalities (P<.001). Conclusion. Patients with abnormal SMPI and ICAD have a 13% event rate of MACE over a two-year follow up. CKD seems a very important marker of a higher risk subgroup amongst such patients.     

经桡动脉途径无保护冠状动脉左主干分叉病变介入治疗

 目的 探讨经桡动脉途径PCI在无保护左主干分叉病变中治疗的可行性和疗效.方法 回顾性分析我院无保护左主干分叉病变择期行PCI的患者22例,21例置入药物洗脱支架,单支架置入7例,双支架置入14例,14例置入双支架的患者均成功进行对吻球囊扩张,1例系支架术后再狭窄,单纯行切割球囊成形术.术后每15 d或1个月门诊复查1次,3～9个月行冠状动脉造影复查.结果 22例PCI均取得成功,术后达TIMI 3级血流,住院期间主要不良心脏事件1例(4.55%),冠状动脉造影复查显示支架内再狭窄2例(10.53%),1例再次行PCI术.术后平均随访(16.86±6.90)个月,随访期内死亡1例.结论 经桡动脉径路无保护左主干分叉病变PCI即刻成功率高,有较好的近、中期疗效.     

Simultaneous assessment of myocardial perfusion and function during mental stress in patients with chronic coronary artery disease

BACKGROUND: Mental stress (MS) is an important provocateur of myocardial ischemia in many patients with chronic coronary artery disease. The majority of laboratory assessments of ischemia in response to MS have included measurements of either myocardial perfusion or function alone. We performed this study to determine the relationship between alterations in perfusion and ventricular function during MS.Methods and results Twenty-eight patients with reversible perfusion defects on exercise or pharmacologic stress myocardial perfusion imaging (MPI) underwent simultaneous technetium 99m sestamibi single photon emission computed tomography (SPECT) MPI and transthoracic echocardiography at rest and during MS according to a mental arithmetic protocol. In all cases the MS study was performed within 4 weeks of the initial exercise or pharmacologic MPI that demonstrated ischemia. SPECT studies were analyzed visually with the use of a 13-segment model and quantitatively by semiautomated circumferential profile analysis. Echocardiograms were graded on a segmental model for regional wall motion on a 4-point scale. Of 28 patients, 18 (64%) had perfusion defects and/or left ventricular dysfunction develop during MS: 9 (32%) had myocardial perfusion defects develop, 6 (21%) had regional or global left ventricular dysfunction develop, and 3 (11%) had both perfusion defects and left ventricular dysfunction develop. The overall concordance between perfusion and function criteria for ischemia during MS was only 46%. Among 9 patients with MS-induced left ventricular dysfunction, 5 had new regional wall motion abnormalities and 4 had a global decrement in function. In patients with MS-induced ischemia by SPECT, the number of reversible perfusion defects was similar during both MS and exercise/pharmacologic stress (2.8 +/- 2.0 vs 3.5 +/- 1.8, P =.41). Hemodynamic changes during MS were similar whether patients were divided on the basis of perfusion defects or left ventricular dysfunction during MS. CONCLUSIONS: These data indicate the feasibility of simultaneous assessment of perfusion and function responses during MS. Flow and function responses to MS are frequently not concordant. These data suggest that MS-induced changes in perfusion may represent a different phenomenon than MS-induced changes in left ventricular function (either globally or regionally).     

Initial experience with X-ray ct based attenuation correction in myocardial perfusion spect imaging using a combined spect/ct system

OBJECTIVE: Attenuation artifacts adversely affect the diagnostic accuracy of myocardial perfusion imaging. We assessed the clinical usefulness of X-ray CT based attenuation correction (AC) in patients undergoing myocardial perfusion imaging by comparing their myocardial AC- and non-corrected (NC) SPECT images with the coronary angiography (CAG). METHODS: We retrospectively reviewed the myocardial SPECT images of 30 patients (18 men, 12 women; mean age 68 years). Thirteen of 30 patients with coronary artery disease (CAD) and 17 without CAD were confirmed by CAG. They underwent sequential CT and myocardial SPECT imaging with thallium-201 (111 MBq) under an exercise or pharmacological stress protocol using our combined SPECT/ CT system. Two readers reviewed the myocardial SPECT images for the presence of CAD on a 4-point scale where 1 = normal, 2 = probably normal, 3 = probably abnormal, and 4 = abnormal. Two reading sessions were held. First, non-corrected (NC)-SPECT and second, AC-SPECT images using X-ray CT images were interpreted. Interobserver variability was assessed with kappa statistics. Diagnostic performance (accuracy) of coronary arterial stenosis was compared between AC- and NC-images. RESULTS: Interobserver agreement for visual assessment was substantial or almost perfect. For AC-images, the observer consensus for analysis was 0.84 for the LAD-, 0.87 for the LCX-, and 0.71 for the RCA-territory. For NC-images, it was 0.91, 0.71, and 0.78. AC resulted in statistically significant improvements in overall diagnostic accuracy (sensitivity/ specificity/accuracy = 76%/93%/89%, 67%/86%/81%, respectively, for AC- and NC-images). CONCLUSIONS: Because of an increase in the specificity, diagnostic accuracy was significantly increased on AC-images. These preliminary data suggest that X-ray CT based AC in myocardial SPECT imaging has the potential to develop into a reliable clinical technique.     

Vascular endothelial dysfunction is associated with reversible myocardial perfusion defects in the absence of obstructive coronary artery disease

Background  The purpose of this study was to investigate whether endothelial dysfunction contributes to abnormal myocardial perfusion imaging (MPI) observed in patients without obstructive coronary artery disease (CAD). It is unclear whether reversible MPI defects detected in the absence of obstructive CAD represent underlying vascular pathology or are false-positive MPI results. Recent evidence suggests that coronary endothelial dysfunction might play a role in the pathogenesis of these defects. Methods and Results  We prospectively recruited 36 patients with chest discomfort, reversible abnormalities on MPI, and nonobstructive or absent CAD (stenosis <50% on coronary angiography). The control group (n = 55) consisted of patients with chest discomfort and similar cardiac risk factors but with normal MPI findings. Vascular endothelial function was assessed in the brachial artery by ultrasound as the response to hyperemia and reported as percent flow-mediated dilation (FMD). Response to sublingual nitroglycerin was used as an indicator of endothelium-independent vasodilation. The patients with abnormal MPI findings and nonobstructive CAD had a significantly lower FMD (9.0% ± 7.2%), indicating endothelial dysfunction, compared with those with similar risk factors and normal MPI findings (12% ± 5.2%) (P ± .03). Baseline brachial artery size and endothelium-independent dilation were similar between groups. On multivariate analysis, only endothelial dysfunction was predictive of reversible MPI defects. Conclusions  Patients with chest pain and reversible MPI defects but without obstructive CAD have lower FMD indicative of endothelial dysfunction, as compared with similar patients with normal MPI findings. The possibility of a causal link between reversible MPI defects and endothelial dysfunction needs further exploration. Dr Soman was funded by the Herbert J. Levine Foundation Fellowship in Cardiovascular Medicine at Tufts-New England Medical Center and the Kos Pharmaceutical Fellowship in Preventive Cardiology during the course of this project.